My baja 5E....sort of

[Maxxman]

To turn down the shaft run the motor whilst in a vice and use a dremel or something similar with a cutting disc to cut down the shaft.
The KB should fit the revo mounts but the holes may have to be off centre if you wish to use the rear support(neu-they have a similar diameter).
Alternatively you could just make a plate with the 30mm bolt spacing and use that instead of the one included.